Mathematical modeling of current density distribution in electrodes of electrosurgical instruments with rectangular working surfaces

Andriі Dubko; Oleksandr Romanenko; Serhii Rymar

doi:10.15222/TKEA2026.1.70

Andriі Dubko E.O. Paton Electric Welding Institute of the NAS of Ukraine, Igor Sikorskyi Kyiv Polytechnic Institute, Kyiv, Ukraine https://orcid.org/0000-0001-6070-3945
Oleksandr Romanenko E.O. Paton Electric Welding Institute of the NAS of Ukraine, Kyiv, Ukraine https://orcid.org/0009-0005-7426-0635
Serhii Rymar E.O. Paton Electric Welding Institute of the NAS of Ukraine, Kyiv, Ukraine https://orcid.org/0000-0003-0490-4608

DOI: https://doi.org/10.15222/TKEA2026.1.70

Keywords: mathematical modeling, electromagnetic processes, rectangular electrosurgical electrodes, current frequency, skin effect, current density distribution

Abstract

This study investigates the influence of the skin effect on electromagnetic processes occurring in the rectangular electrodes of electrosurgical instruments during alternating current flow. The mathematical modeling was performed by solving partial differential equations using the numerical finite element method. The simulation results demonstrate an uneven current density distribution along the perimeter of the rectangular electrode. The current is highly concentrated in the corners of the electrode and is practically absent in its center. The active resistance of a copper rectangular electrode (with a cross-section of 3 х 15 mm and a length 3 mm) was analyzed within the frequency range of 22 to 880 kHz. It was established that increasing the current frequency leads to higher joule heating losses in the electrodes due to a reduction in the effective cross-sectional area caused by the skin effect. Modifying the electrode geometry by rounding its corners allows for equalizing the current density distribution and reducing the total resistance.

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